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Structural Engineering and Mechanics
  Volume 74, Number 3, May10 2020, pages 407-423

Experimental and numerical study on pre-peak cyclic shear mechanism of artificial rock joints
Xinrong Liu, Yongquan Liu, Yuming Lu and Miaomiao Kou

    The pre-peak cyclic shear mechanism of two-order asperity degradation of rock joints in the direct shear tests with static constant normal loads (CNL) are investigated using experimental and numerical methods. The laboratory testing rock specimens contains the idealized and regular two-order triangular-shaped asperities, which represent the specific geometrical conditions of natural and irregular waviness and unevenness of rock joint surfaces, in the pre-peak cyclic shear tests. Three different shear failure patterns of two-order triangular-shaped rock joints can be found in the experiments at constant horizontal shear velocity and various static constant normal loads in the direct and pre-peak cyclic shear tests. The discrete element method is adopted to simulate the pre-peak shear failure behaviors of rock joints with two-order triangular-shaped asperities. The rock joint interfaces are simulated using a modified smooth joint model, where microscopic scale slip surfaces are applied at contacts between discrete particles in the upper and lower rock blocks. Comparing the discrete numerical results with the experimental results, the microscopic bond particle model parameters are calibrated. Effects of cyclic shear loading amplitude, static constant normal loads and initial waviness asperity angles on the pre-peak cyclic shear failure behaviors of triangular-shaped rock joints are also numerically investigated.
Key Words
    Pre-peak cyclic shear; Two-order asperity degradation; Shear failure modes; DEM; Numerical simulation
Xinrong Liu: School of Civil Engineering, Chongqing University, Chongqing 400045, P.R. China
Yongquan Liu: School of Civil Engineering, Chongqing University, Chongqing 400045, P.R. China; China Construction Underground Space Co., Ltd., Chengdu, 610081, P.R. China
Yuming Lu: School of Civil Engineering, Chongqing University, Chongqing 400045, P.R. China; Chongqing No.7 Construction Engineering Co., Ltd., Chongqing, 400059, P.R. China
Miaomiao Kou: School of Civil Engineering, Qingdao University of Technology, Qingdao, 266033, China
Cooperative Innovation Center of Engineering Construction and Safety in Shandong Blue Economic Zone, Qingdao, 266033, China

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